Dynamical modelling of power systems with power electronic controllers using individual channel analysis and design

Global demand for electrical energy is at an all time high. In industrialised societies consumers have come to expect an interruption-free, high-quality electricity supply and environmentally aware consumers and pressure groups have been very successful in encouraging the electricity supply industry towards incorporating, as part of the generation mix, sources of electricity that are benign to the environment. In some European countries great progress has been made in the integration of wind generation and photo-voltaics. Moreover, the industry has gone through major privatisation and deregulation programmes worldwide; and there is the notion in some quarters that deregulation and widespread cross-border interconnections may have exacerbated the incidence of wide-area break-downs in electricity supply. The challenges facing today’s electricity supply industry are many, and the technology to deliver the necessary grid control is still underdeveloped. A major research thrust is required to make a power network flexible, resilient and responsive to the consumer’s wishes of being supplied with environmentally sound electricity. Renewable generation such as wind and marine turbines and photo-voltaic cells need power electronics and effective controllers if they are to be successfully integrated into the electricity grid without reduction of supply quality. The dynamical interaction of multi-machine networks, power electronics and large penetration of intermittent generation are highly complex phenomena and a better understanding of their dynamical behaviour is mandatory before larger increases of intermittent generation are added to it, to avoid widespread black-outs and thwarted energy transactions. The impact of successful integration of FACTS equipment into power systems networks worldwide is affecting all sectors of the market: power generation, transmission, distribution, utilisation and equipment manufacturers. However, further progress requires investigating further the dynamic performance of the FACTS technology in order to continue acquiring leading-edge, relevant knowledge. Devices used to enhance the stability of power systems such as the Static VAr Compensator (SVC) and the Thyristor-Controlled Series Compensator (TCSC) are prime candidates for investigation owing to their popularity. Both FACTS controllers are comprehensively investigated in this research. The main aims of this research project are to develop and evaluate dynamic high-order multi-machine models, dynamic models of FACTS devices, such as the SVC and the TCSC, with particular emphasis in their electromechanical oscillations damping capabilities; to carry out fundamental analyses and control system designs of synchronous generators and FACTS controllers; and to investigate their dynamic effects and interactions with the power network. Individual Channel Analysis and Design (ICAD), a classical oriented multivariable control systems framework is used in this research project. ICAD has shown its suitability for carrying out small-signal stability assessments, with which it has been possible to evaluate the potential robustness and performance of the control system design, affording physical insight.